With the continued increase in Internet traffic, data centers have been utilizing network appliances to offload some of the more intensive processing tasks from servers. Network appliances typically intercept packets communicated between a client and a server, and have specialized hardware or software to increase processing speeds for certain types of packet data. For example, a network appliance may be specifically designed to process Secure Socket Layer (SSL) or Extensible Markup Language (XML) packets. In the case of an SSL network appliance, for example, the appliance may perform the processor intensive task of encrypting and decrypting data, thereby reducing processing demands on the server.
Network appliances may be cascaded to increase the overall processing power for a system. In addition, this may provide a form of fault tolerance. If one appliance becomes inoperative, the others may continue performing the intended task. To operate efficiently, cascaded network appliances typically require some form of load balancing to ensure work is properly distributed among the cascaded devices. Conventional solutions to perform load balancing, however, may be unsatisfactory for a number of reasons. For example, one solution may monitor certain threshold parameters for each appliance and allocate packets accordingly. As demands for faster packet processing increase, however, the threshold parameters may change faster than the load balancing algorithm can properly handle. Further, monitoring threshold parameters is premised upon statistical approximations for load balancing, and therefore may not operate as efficiently during practical implementation. Consequently, there may be a need for improved load balancing techniques to solve these and other problems.